BACKGROUND： Previous studies have indicated preventive acupuncture and moxibustion at the Guanyuan point have positive effects on the immune system of menopausal rats. OBJECTIVE： To observe the effects of preventive...BACKGROUND： Previous studies have indicated preventive acupuncture and moxibustion at the Guanyuan point have positive effects on the immune system of menopausal rats. OBJECTIVE： To observe the effects of preventive acupuncture or moxibustion at the Guanyuan point on interleukin-2 （IL-2） and its receptor （IL-2R mRNA） levels in hypothalamus, serum, and uterus of menopausal rats. DESIGN： Randomized control animal experiment. SETTING： School of Acupuncture and Moxibustion, Beijing University of Chinese Medicine. MATERIALS： This study was performed at the Laboratory of Beijing University of Chinese Medicine from November 2004 to July 2005. The vaginal smear method was used to determine the estrus cycle of 9.5-month-old Sprague Dawley （SD） female rats. Three continuous estrus cycles were measured, and 160 rats with estrus cycle disorder, weighing （300 _＋ 20） g, were included in this study. The rats were randomly divided into four groups： preventive acupuncture group （n =48）, preventive moxibustion group （n =48）, model groups （n =48）, and 10-month-old group （n =16）. Sixteen 3.5-month-old healthy SD female rats, weighing （240 ± 20） g, were also assigned to the young group. All rats were clean grade and were purchased from the Laboratory Animal Center, Beijing University of Chinese Medicine. The experiment was in accordance with animal ethics standards. METHODS： Acupuncture was applied to the preventive acupuncture group at 10 months of age. The needle was inserted upward and perpendicularly two fen to a point that was two fen below the Guanyuan point. The rats freely moved around during needle retention （20 minutes）. Acupuncture was administered twice a week and continued for eight weeks. A moxa cone （small） moxibustion was applied to the preventive moxibustion group at 10 months of age. The rats were caught gently and kept at the same position as the preventive acupuncture group. The moxa cone was ignited and held to the Guanyuan point directly. Only one moxa cone was used each time. After moxibustion, the local skin turned slightly red. Moxibustion was used twice a week and continued for eight weeks. Nothing except gently catching and lying was administered to the model group and the young group. MAIN OUTCOME MEASURES： Radioimmunoassay, in situ hybridization, and similar methods were employed to detect IL-2 in serum and the uterus, as well as IL-2R mRNA expression in the hypothalamus and uterus arcuate nuclei, of the preventive acupuncture group, preventive moxibustion group, model groups （at 12, 14, and 16 months）, 10 month old group （at 10 months）, and the young group （at 4 months）. RESULTS： All 176 rats were included in the final analysis. （1） IL-2R mRNA： IL-2R mRNA expression decreased significantly in the uterus of 12-, 14-, and 16-month-old model groups and in the hypothalamus of 14- and 16-month-old model groups （P 〈 0.05-0.01）. Compared to the same month-aged model groups, the expression of IL-2R mRNA increased significantly in the hypothalamus and uterus of 16-month-old preventive acupuncture or moxibustion groups （P 〈 0.05-0.01）.（2） IL-2：IL-2 in serum of 12- and 14-month-old model groups and in the uterus of 12-, 14-, and 16-month-old model groups decreased significantly compared to the young group （P 〈 0.05-0.01）. IL-2 serum levels increased significantly in the 16-month-old group with preventive moxibustion; in addition, IL-2 expression levels increased significantly in the uterus of the 12-month-old group with preventive moxibustion, as well as the 12- and 16-month-old groups with preventive acupuncture （P 〈 0.05-0.01）. CONCLUSION： As a rat ages and becomes menopausal, IL-2R mRNA expression in the hypothalamus and uterus, as well as IL-2 levels in the serum and uterus, decrease. However, preventive acupuncture and preventive moxibustion can repress the decrease to some extent. This effect is even greater in the late stages of menopause （16-month-old rats）.展开更多
Treatments of atherogenesis,one of the most common cardiovascular diseases(CVD),are continuously being made thanks to innovation and an increasingly in-depth knowledge of percutaneous transluminal coronary angioplasty...Treatments of atherogenesis,one of the most common cardiovascular diseases(CVD),are continuously being made thanks to innovation and an increasingly in-depth knowledge of percutaneous transluminal coronary angioplasty(PTCA),the most revolutionary medical procedure used for vascular restoration.Combined with an expanding balloon,vascular stents used at stricture sites enable the long-time restoration of vascular permeability.However,complication after stenting,in-stent restenosis(ISR),hinders the advancement of vascular stents and are associated with high medical costs for patients for decades years.Thus,the development of a high biocompatibility stent with improved safety and efficiency is urgently needed.This review provides an overview of current advances and potential technologies for the modification of stents for better treatment and prevention of ISR.In particular,the mechanisms of in-stent restenosis are investigated and summarized with the aim to comprehensively understanding the pathogenesis of stent complications.Then,according to different therapeutic functions,the current stent modification strategies are reviewed,including polymeric drug eluting stents,biological friendly stents,prohealing stents,and gene stents.Finally,the review provides an outlook of the challenges in the design of stents with optimal properties.Therefore,this review is a valuable and practical guideline for the development of cardiovascular stents.展开更多
Therapeutic resistance in cancer is responsible for numerous cancer deaths in clinical practice.While target mutations are well recognized as the basis of genetic resistance to targeted therapy,nontarget mutation resi...Therapeutic resistance in cancer is responsible for numerous cancer deaths in clinical practice.While target mutations are well recognized as the basis of genetic resistance to targeted therapy,nontarget mutation resistance(or nongenetic resistance)remains poorly characterized.Despite its complex and unintegrated mechanisms in the literature,nongenetic resistance is considered from our perspective to be a collective response of innate or acquired resistant subpopulations in heterogeneous tumors to therapy.These subpopulations,e.g.,cancer stem-like cells,cancer cells with epithelial-to-mesenchymal transition,and drug-tolerant persisters,are protected by their resistance traits at cellular and molecular levels.This review summarizes recent advances in the research on resistant populations and their resistance traits.NOTCH signaling,as a central regulator of nongenetic resistance,is discussed with a special focus on its canonical maintenance of resistant cancer cells and noncanonical regulation of their resistance traits.This novel view of canonical and noncanonical NOTCH signaling pathways is translated into our proposal of reshaping therapeutic strategies targeting NOTCH signaling in resistant cancer cells.We hope that this review will lead researchers to study the canonical and noncanonical arms of NOTCH signaling as an integrated resistant mechanism,thus promoting the development of innovative therapeutic strategies.展开更多
The cytomembrane-derived delivery platform represents a promising biomimetic strategy in oncotherapy.To achieve durable and reliable tumor inhibition,mature dendrosomes(mDs),which were isolated from bone marrow-derive...The cytomembrane-derived delivery platform represents a promising biomimetic strategy in oncotherapy.To achieve durable and reliable tumor inhibition,mature dendrosomes(mDs),which were isolated from bone marrow-derived dendritic cells undergoing CT26 tumor antigen(TA)stimulation,were fused with redox-responsive nanoparticles(NPs)that were composed of poly(disulfide ester amide)polymers with an intensified disulfide density and hydrophobic oxaliplatin(OXA)prodrugs with the ability to potentiate immunogenicity.In vitro and in vivo results revealed that NP/mDs could induce tumor cell death through mitochondrial pathway and thus created immunogenic microenvironments,but also elicited immunocyte differentiation by TA cross-dressing and infiltration by direct presentation.By further neutralizing immune-regulatory interaction,the administration of PD-L1 antibody(αPD-L1)greatly improved antitumor efficiency of NP/mDs.Furthermore,the effectors of host immune systems effectively inhibited the growth and metastasis of distal tumors,likely because the autologous TA evoked by OXA and allogeneic TA delivered by mDs acted as additional stimuli to reinforce the immune response of tumor-specific T cells and immunosurveillance toward oncogenesis.These results demonstrated that NP/mDs could simultaneously realize immunogenic chemotherapeutics and specific TA delivery.In combination withαPD-L1,the antitumor effect was further enhanced.Therefore,NP/mDs provide a promising strategy for the comprehensive treatment of malignancy.展开更多
Taking inspiration from nature, the biomimetic concept has been integrated into drug delivery systems in cancer therapy. Disguised with cell membranes, the nanoparticles can acquire various functions of natural cells....Taking inspiration from nature, the biomimetic concept has been integrated into drug delivery systems in cancer therapy. Disguised with cell membranes, the nanoparticles can acquire various functions of natural cells. The cell membrane-coating technology has pushed the limits of common nano-systems(fast elimination in circulation) to more effectively navigate within the body. Moreover, because of the various functional molecules on the surface, cell membrane-based nanoparticles(CMBNPs) are capable of interacting with the complex biological microenvironment of the tumor. Various sources of cell membranes have been explored to camouflage CMBNPs and different tumor-targeting strategies have been developed to enhance the anti-tumor drug delivery therapy. In this review article we highlight the most recent advances in CMBNP-based cancer targeting systems and address the challenges and opportunities in this field.展开更多
Although nanotechnology has been rapidly developed and applied in tumor targeting, the outcome of chemotherapy remains greatly restricted by the toxicity of cytotoxic drugs in normal tissues and cells. Therefore, the ...Although nanotechnology has been rapidly developed and applied in tumor targeting, the outcome of chemotherapy remains greatly restricted by the toxicity of cytotoxic drugs in normal tissues and cells. Therefore, the development of alternative delivery systems, with few side effects in normal cells, has attracted increasing attention. Energy restriction is a novel and promising approach to cancer treatment, which can restrict tumor growth via inhibition of cellular energy metabolism. In this study, a novel tumor targeting system, based on folate-conjugated bovine serum albumin （BSA）, was developed to co-deliver albendazole and nanosilver simultaneously, to restrain the energy metabolism of tumor cells. This nanosystem showed stronger anti-tumor efficacy than those using nanoparticles without folic acid modification, nanosilver, or albendazole, both in vitro and in vivo. This nanosystem depleted cellular ATP via direct inhibition of glycolytic enzymes and mitochondrial damage, resulting in inhibition of proliferation, cell-cycle arrest, and apoptosis of tumor cells. The enhanced anti-tumor activity contributed to the tumor-targeting ability of this system, resulting in specific energy inhibition in tumor cells. Toxicity evaluation was performed to confirm the safety of this system. This nanosystem provides an efficient and safe strate~ for tumor therapy.展开更多
The ethanol oxidation reaction(EOR)is crucial in direct alcohol fuel cells and chemical production.However,the electro-oxidation of ethanol molecules to produce acetaldehyde and carbon monoxide can poison the active s...The ethanol oxidation reaction(EOR)is crucial in direct alcohol fuel cells and chemical production.However,the electro-oxidation of ethanol molecules to produce acetaldehyde and carbon monoxide can poison the active sites of nanocatalysts,resulting in reduced performance and posing challenges in achieving high activity and selectivity for ethanol oxidation.In this study,we employed a dynamic seed-mediated method to precisely modify highly dispersed Ru sites onto well-defined Pd nanocrystals.The oxyphilic Ru sites serve as"OH valves",regulating water dissociation,while the surrounding Pd atomic arrangements control electronic states for the oxidation dehydrogenation of carbonaceous intermediates.Specifically,Ru0.040@Pd nanocubes(Ru:Pd=0.04 at.%),featuring(100)facets in Ru-Pd4 configurations,demonstrate an outstanding mass activity of 6.53 A·mgPd^(-1) in EOR under alkaline conditions,which is 6.05 times higher than that of the commercial Pd/C catalyst(1.08 A·mgPd-1).Through in-situ experiments and theoretical investigations,we elucidate that the hydrophilic Ru atoms significantly promote the dynamic evolution of H_(2)O dissociation into OHads species,while the electron redistribution from Ru to adjacent Pd concurrently adjusts the selective oxidation of C_(2) intermediates.This host-vip interaction accelerates the subsequent oxidation of carbonaceous intermediates(CH_(3)CO_(ads))to acetate,while preventing the formation of toxic*CHx and*CO species,which constitutes the rate-determining step.展开更多
Increasing the utilization efficiency of platinum is critical for advancing proton exchange-membrane fuel cells(PEMFCs).Despite extensive research on catalysts for the cathodic oxygen reduction reaction(ORR),developin...Increasing the utilization efficiency of platinum is critical for advancing proton exchange-membrane fuel cells(PEMFCs).Despite extensive research on catalysts for the cathodic oxygen reduction reaction(ORR),developing highly active and durable Pt-based catalysts that can suppress surface dealloying in corrosive acid conditions remains challenging.Herein,we report a facile synthesis of bimetallic ultrathin PtM(M=Mo,W,and Cr)nanowires(NWs)composed of group VI B transition metal atomic sites anchored on the surface.These NWs possess uniform sizes and well-controlled atomic arrangements.Compared to PtW and PtCr catalysts,the PtMo0.05 NWs exhibit the highest half-wave potential of 0.935 V and a mass activity of 1.43 A·mgPt^(−1).Remarkably,they demonstrate a remarkable 23.8-fold enhancement in mass activity compared to commercial Pt/C for ORR,surpassing previously reported Pt-based catalysts.Additionally,the PtMo NWs cathode in membrane electrode assembly tests achieves a remarkable peak power density of 1.443 W·cm^(−2)(H_(2)-O_(2)conditions at 80℃),which is 1.09 times that of commercial Pt/C.The ligand effect in the bimetallic surface not only facilitates strong coupling between Mo(4d)and Pt(5d)atomic orbitals to hinder atom leaching but also modulates the d-states of active site,significantly optimizing the adsorption of key oxygen(*O and*OH)species and accelerating the rate-determining step in ORR pathways.展开更多
基金the National Nature Science Foundation of China, No. 90209026Natural Science Foundation of Beijing, No. 7052037
文摘BACKGROUND： Previous studies have indicated preventive acupuncture and moxibustion at the Guanyuan point have positive effects on the immune system of menopausal rats. OBJECTIVE： To observe the effects of preventive acupuncture or moxibustion at the Guanyuan point on interleukin-2 （IL-2） and its receptor （IL-2R mRNA） levels in hypothalamus, serum, and uterus of menopausal rats. DESIGN： Randomized control animal experiment. SETTING： School of Acupuncture and Moxibustion, Beijing University of Chinese Medicine. MATERIALS： This study was performed at the Laboratory of Beijing University of Chinese Medicine from November 2004 to July 2005. The vaginal smear method was used to determine the estrus cycle of 9.5-month-old Sprague Dawley （SD） female rats. Three continuous estrus cycles were measured, and 160 rats with estrus cycle disorder, weighing （300 _＋ 20） g, were included in this study. The rats were randomly divided into four groups： preventive acupuncture group （n =48）, preventive moxibustion group （n =48）, model groups （n =48）, and 10-month-old group （n =16）. Sixteen 3.5-month-old healthy SD female rats, weighing （240 ± 20） g, were also assigned to the young group. All rats were clean grade and were purchased from the Laboratory Animal Center, Beijing University of Chinese Medicine. The experiment was in accordance with animal ethics standards. METHODS： Acupuncture was applied to the preventive acupuncture group at 10 months of age. The needle was inserted upward and perpendicularly two fen to a point that was two fen below the Guanyuan point. The rats freely moved around during needle retention （20 minutes）. Acupuncture was administered twice a week and continued for eight weeks. A moxa cone （small） moxibustion was applied to the preventive moxibustion group at 10 months of age. The rats were caught gently and kept at the same position as the preventive acupuncture group. The moxa cone was ignited and held to the Guanyuan point directly. Only one moxa cone was used each time. After moxibustion, the local skin turned slightly red. Moxibustion was used twice a week and continued for eight weeks. Nothing except gently catching and lying was administered to the model group and the young group. MAIN OUTCOME MEASURES： Radioimmunoassay, in situ hybridization, and similar methods were employed to detect IL-2 in serum and the uterus, as well as IL-2R mRNA expression in the hypothalamus and uterus arcuate nuclei, of the preventive acupuncture group, preventive moxibustion group, model groups （at 12, 14, and 16 months）, 10 month old group （at 10 months）, and the young group （at 4 months）. RESULTS： All 176 rats were included in the final analysis. （1） IL-2R mRNA： IL-2R mRNA expression decreased significantly in the uterus of 12-, 14-, and 16-month-old model groups and in the hypothalamus of 14- and 16-month-old model groups （P 〈 0.05-0.01）. Compared to the same month-aged model groups, the expression of IL-2R mRNA increased significantly in the hypothalamus and uterus of 16-month-old preventive acupuncture or moxibustion groups （P 〈 0.05-0.01）.（2） IL-2：IL-2 in serum of 12- and 14-month-old model groups and in the uterus of 12-, 14-, and 16-month-old model groups decreased significantly compared to the young group （P 〈 0.05-0.01）. IL-2 serum levels increased significantly in the 16-month-old group with preventive moxibustion; in addition, IL-2 expression levels increased significantly in the uterus of the 12-month-old group with preventive moxibustion, as well as the 12- and 16-month-old groups with preventive acupuncture （P 〈 0.05-0.01）. CONCLUSION： As a rat ages and becomes menopausal, IL-2R mRNA expression in the hypothalamus and uterus, as well as IL-2 levels in the serum and uterus, decrease. However, preventive acupuncture and preventive moxibustion can repress the decrease to some extent. This effect is even greater in the late stages of menopause （16-month-old rats）.
基金financial support from the National Key Research and Development Program of China(2017YFB0702500)Natural Science Foundation of China(NSFC Project,81801853)Sichuan Science and Technology Program(19GJHZ0058)。
文摘Treatments of atherogenesis,one of the most common cardiovascular diseases(CVD),are continuously being made thanks to innovation and an increasingly in-depth knowledge of percutaneous transluminal coronary angioplasty(PTCA),the most revolutionary medical procedure used for vascular restoration.Combined with an expanding balloon,vascular stents used at stricture sites enable the long-time restoration of vascular permeability.However,complication after stenting,in-stent restenosis(ISR),hinders the advancement of vascular stents and are associated with high medical costs for patients for decades years.Thus,the development of a high biocompatibility stent with improved safety and efficiency is urgently needed.This review provides an overview of current advances and potential technologies for the modification of stents for better treatment and prevention of ISR.In particular,the mechanisms of in-stent restenosis are investigated and summarized with the aim to comprehensively understanding the pathogenesis of stent complications.Then,according to different therapeutic functions,the current stent modification strategies are reviewed,including polymeric drug eluting stents,biological friendly stents,prohealing stents,and gene stents.Finally,the review provides an outlook of the challenges in the design of stents with optimal properties.Therefore,this review is a valuable and practical guideline for the development of cardiovascular stents.
基金supported by the National Natural Science Foundation of China(Nos.81974455,8217110405,and 82173351)the National Key Research and Development Program of China(No.2018YFA0107800)the Zhejiang University Startup Fund for Dr.Wei Guo.Special thanks also go to the Mu Xian Hua Stem Cells and Cancer Resistance Fund.
文摘Therapeutic resistance in cancer is responsible for numerous cancer deaths in clinical practice.While target mutations are well recognized as the basis of genetic resistance to targeted therapy,nontarget mutation resistance(or nongenetic resistance)remains poorly characterized.Despite its complex and unintegrated mechanisms in the literature,nongenetic resistance is considered from our perspective to be a collective response of innate or acquired resistant subpopulations in heterogeneous tumors to therapy.These subpopulations,e.g.,cancer stem-like cells,cancer cells with epithelial-to-mesenchymal transition,and drug-tolerant persisters,are protected by their resistance traits at cellular and molecular levels.This review summarizes recent advances in the research on resistant populations and their resistance traits.NOTCH signaling,as a central regulator of nongenetic resistance,is discussed with a special focus on its canonical maintenance of resistant cancer cells and noncanonical regulation of their resistance traits.This novel view of canonical and noncanonical NOTCH signaling pathways is translated into our proposal of reshaping therapeutic strategies targeting NOTCH signaling in resistant cancer cells.We hope that this review will lead researchers to study the canonical and noncanonical arms of NOTCH signaling as an integrated resistant mechanism,thus promoting the development of innovative therapeutic strategies.
基金We acknowledge the financial support of the National Natural Science Foundation of China （Nos. 81690263, 81472757, 81361140344, 81773283, and 81773911）. Thanks are given to Dr. Yang Yang from Shanghai University of Traditional Chinese Medicine for his kind help with the CIA model.
基金supported by the National Natural Science Foundation of China(No.81773911,81690263 and 81573616)the Development Project of Shanghai Peak Disciplines-Integrated Medicine(No.20180101).
文摘The cytomembrane-derived delivery platform represents a promising biomimetic strategy in oncotherapy.To achieve durable and reliable tumor inhibition,mature dendrosomes(mDs),which were isolated from bone marrow-derived dendritic cells undergoing CT26 tumor antigen(TA)stimulation,were fused with redox-responsive nanoparticles(NPs)that were composed of poly(disulfide ester amide)polymers with an intensified disulfide density and hydrophobic oxaliplatin(OXA)prodrugs with the ability to potentiate immunogenicity.In vitro and in vivo results revealed that NP/mDs could induce tumor cell death through mitochondrial pathway and thus created immunogenic microenvironments,but also elicited immunocyte differentiation by TA cross-dressing and infiltration by direct presentation.By further neutralizing immune-regulatory interaction,the administration of PD-L1 antibody(αPD-L1)greatly improved antitumor efficiency of NP/mDs.Furthermore,the effectors of host immune systems effectively inhibited the growth and metastasis of distal tumors,likely because the autologous TA evoked by OXA and allogeneic TA delivered by mDs acted as additional stimuli to reinforce the immune response of tumor-specific T cells and immunosurveillance toward oncogenesis.These results demonstrated that NP/mDs could simultaneously realize immunogenic chemotherapeutics and specific TA delivery.In combination withαPD-L1,the antitumor effect was further enhanced.Therefore,NP/mDs provide a promising strategy for the comprehensive treatment of malignancy.
基金the financial support from National Natural Science Foundation of China (81773911, 81690263, 81673372, and 81361140344)National Basin Research Program of China (2013CB 932500)Development Project of Shanghai Peak Disciplines– Integrated Medicine (No. 20150407)
文摘Taking inspiration from nature, the biomimetic concept has been integrated into drug delivery systems in cancer therapy. Disguised with cell membranes, the nanoparticles can acquire various functions of natural cells. The cell membrane-coating technology has pushed the limits of common nano-systems(fast elimination in circulation) to more effectively navigate within the body. Moreover, because of the various functional molecules on the surface, cell membrane-based nanoparticles(CMBNPs) are capable of interacting with the complex biological microenvironment of the tumor. Various sources of cell membranes have been explored to camouflage CMBNPs and different tumor-targeting strategies have been developed to enhance the anti-tumor drug delivery therapy. In this review article we highlight the most recent advances in CMBNP-based cancer targeting systems and address the challenges and opportunities in this field.
文摘Although nanotechnology has been rapidly developed and applied in tumor targeting, the outcome of chemotherapy remains greatly restricted by the toxicity of cytotoxic drugs in normal tissues and cells. Therefore, the development of alternative delivery systems, with few side effects in normal cells, has attracted increasing attention. Energy restriction is a novel and promising approach to cancer treatment, which can restrict tumor growth via inhibition of cellular energy metabolism. In this study, a novel tumor targeting system, based on folate-conjugated bovine serum albumin （BSA）, was developed to co-deliver albendazole and nanosilver simultaneously, to restrain the energy metabolism of tumor cells. This nanosystem showed stronger anti-tumor efficacy than those using nanoparticles without folic acid modification, nanosilver, or albendazole, both in vitro and in vivo. This nanosystem depleted cellular ATP via direct inhibition of glycolytic enzymes and mitochondrial damage, resulting in inhibition of proliferation, cell-cycle arrest, and apoptosis of tumor cells. The enhanced anti-tumor activity contributed to the tumor-targeting ability of this system, resulting in specific energy inhibition in tumor cells. Toxicity evaluation was performed to confirm the safety of this system. This nanosystem provides an efficient and safe strate~ for tumor therapy.
基金supported by the National Natural Science Foundation of China(No.22275009)SINOPEC(Contact No.421028)Fundamental Research Funds for the Central Universities(No.XK2020-02).
文摘The ethanol oxidation reaction(EOR)is crucial in direct alcohol fuel cells and chemical production.However,the electro-oxidation of ethanol molecules to produce acetaldehyde and carbon monoxide can poison the active sites of nanocatalysts,resulting in reduced performance and posing challenges in achieving high activity and selectivity for ethanol oxidation.In this study,we employed a dynamic seed-mediated method to precisely modify highly dispersed Ru sites onto well-defined Pd nanocrystals.The oxyphilic Ru sites serve as"OH valves",regulating water dissociation,while the surrounding Pd atomic arrangements control electronic states for the oxidation dehydrogenation of carbonaceous intermediates.Specifically,Ru0.040@Pd nanocubes(Ru:Pd=0.04 at.%),featuring(100)facets in Ru-Pd4 configurations,demonstrate an outstanding mass activity of 6.53 A·mgPd^(-1) in EOR under alkaline conditions,which is 6.05 times higher than that of the commercial Pd/C catalyst(1.08 A·mgPd-1).Through in-situ experiments and theoretical investigations,we elucidate that the hydrophilic Ru atoms significantly promote the dynamic evolution of H_(2)O dissociation into OHads species,while the electron redistribution from Ru to adjacent Pd concurrently adjusts the selective oxidation of C_(2) intermediates.This host-vip interaction accelerates the subsequent oxidation of carbonaceous intermediates(CH_(3)CO_(ads))to acetate,while preventing the formation of toxic*CHx and*CO species,which constitutes the rate-determining step.
基金the National Natural Science Foundation of China(No.22275009)SINOPEC(contact No.421028)Fundamental Research Funds for the Central Universities(No.XK2020-02).
文摘Increasing the utilization efficiency of platinum is critical for advancing proton exchange-membrane fuel cells(PEMFCs).Despite extensive research on catalysts for the cathodic oxygen reduction reaction(ORR),developing highly active and durable Pt-based catalysts that can suppress surface dealloying in corrosive acid conditions remains challenging.Herein,we report a facile synthesis of bimetallic ultrathin PtM(M=Mo,W,and Cr)nanowires(NWs)composed of group VI B transition metal atomic sites anchored on the surface.These NWs possess uniform sizes and well-controlled atomic arrangements.Compared to PtW and PtCr catalysts,the PtMo0.05 NWs exhibit the highest half-wave potential of 0.935 V and a mass activity of 1.43 A·mgPt^(−1).Remarkably,they demonstrate a remarkable 23.8-fold enhancement in mass activity compared to commercial Pt/C for ORR,surpassing previously reported Pt-based catalysts.Additionally,the PtMo NWs cathode in membrane electrode assembly tests achieves a remarkable peak power density of 1.443 W·cm^(−2)(H_(2)-O_(2)conditions at 80℃),which is 1.09 times that of commercial Pt/C.The ligand effect in the bimetallic surface not only facilitates strong coupling between Mo(4d)and Pt(5d)atomic orbitals to hinder atom leaching but also modulates the d-states of active site,significantly optimizing the adsorption of key oxygen(*O and*OH)species and accelerating the rate-determining step in ORR pathways.
